High Specific Activity Sn-117m by Post Irradiation Isotope Separation

The radioisotope tin-117m (117mSn) is a theranostic isotope that is suitable for both diagnostic and therapeutic applications. Its low energy gamma rays can be imaged using standard gamma cameras. For therapy its short-range ( & lt;300 micron) conversion electrons minimize damage to healthy tissue. These emissions, along with its 13.6-day half-life, make tin-117m of interest in a variety of biomedical applications, including several in the fields of oncology and cardiology. While tin-117m can be produced through a variety of methods, there are limiting factors that must be addressed in order to facilitate drug development and commercialization efforts. Tin-117m can be produced in large quantities in reactors; however, the low ( & lt;20 Ci/g) specific activity (SA) product is not suitable for many clinical applications. For example in receptor-targeted therapies, where there are a limited number of receptor sites, mid SA ( & gt;100 Ci/g) and/or high SA ( & gt;1,000 Ci/g) material is required. High SA material is available using accelerator-based production methods, but the small number of suitable accelerators limits quantities available to less than a few Ci per week. Expected future commercial demands will likely require tens of Ci per week of mid and high SA material. Meeting the anticipated need can only be realized with the construction of many costly new accelerators or with a new approach for producing mid and high SA material. Our goal in this project is to determine the technical and economic feasibility of producing mid and high SA tin-117m by electromagnetic (EM) mass separation of readily available low SA reactor-produced material. EM mass separation is used in the production of enriched stable isotopes; however, the successful development of an economically viable EM facility for the production of short-lived medical isotopes presents new challenges. Primary issues involve ion source performance and overall process efficiency. Phase I will focus on issues related to ion source and process development. We aim to intensively study ion source performance in order to determine the optimal combination of feedstock material (e.g. metal or chloride) and ion source. In addition, we intend to measure efficiency of key process steps that influence total production yields and economics. Commercial Applications and Other Benefits: Given the excellent nuclear properties of tin-117m and its potential use as a theranostic isotope, the commercial prospects are outstanding. With the development of a technique to produce the desired specific activity levels, these prospects would be realized. The ultimate objective is to develop and deploy a commercially viable Therapeutic Isotope Separator Facility in partnership with stakeholders. This effort would support drug development efforts that could lead to important patient benefits.